KIN 300 Angular Kinetics and Kinematics

A baseball bat is swung with an angular velocity of 500 degrees/second and has a radius of 1.2cm. What is the linear velocity of the baseball bat?

10.47 m/s

During a flipping motion, how would a person increase their moment of inertia of the whole body?

Stick their arms and legs further from the Com

Which of the following is a major study of angular kinetics?

Torque

You recently decided to take up power walking. However today there is a massive headwind of 15 m/s and you want to maintain a constant walking velocity of 2 m/s. You rock your skin tight suit and you power walking helmet which reduces your drag coefficient and surface area to 0.15m². How much drag force is created if the air density is 1.2 kg/m³?

26.0 N

If the knee starts in a static position (180 deg) and moves to a 90 deg position over a 0.2s time period, what is the average angular acceleration of the knee?

2250 degrees/s²

What is the moment of inertia of a baseball bat about its proximal end if its mass is 2.1 kg and has a radius of gyration  of 58% and a length of 0.869m?

0.533 kg/m²

Which of the following lines has the fastest linear velocity in the image below?

C

What is the force which acts perpendicular to the direction of travel of an object?

Lift force

Which of the following muscles is responsible for eccentric horizontal abduction of the shoulder?

Pectoralis major

How much lift force is present when the relative velocity of the object and the fluid is 3 m/s, and the fluid density is 1.2 and the l is 0.367?

1.98 N

If the hip moves through 75 degrees over a 0.2s time period, what was its average angular velocity?

375 deg/s

If segment A is 2m and segment B is 1.3, what is the relative angle between the two segments if the “C’; length is 2.5m?

96.2 deg

Generally speaking, this quantity is essential in equating linear and angular velocity, as it is explicitly written in all of the linear to angular kinematics equations

Radius

If the elbow starts at a 90 deg flexed position (the relative angle between the humerus and ulna) and ends with a 175 deg position, how much range of motion did it go through?

85 deg extension

A leg swung about the knee joint is an example of angular kinematics. If the leg is 0.41m long and rotates 45 degrees, what is the linear displacement?

0.32 m

During a softball pitch, the shoulder goes through 380 deg of motion. If the desired angular velocity is 678 deg/s, how long should the motion take to complete?

0.56s

If a segment has distal coordinates of (3,2) and proximal coordinates of (8,8), what is the absolute angle of the segment?

50.2 deg

The force created by a fluid which acts perpendicular to the direction of motion is known as what?

Lift force

Which is the following is true when angular momentum is conserved?

Summation of external torques equals zero

While walking, the hip goes through 40 degrees of flexion during the early part of the stance phase which lasts 0.25s. What is the angular velocity of the hip flexion?

160 deg/s

During a soccer kick in the kicking leg, the hip moves from 175 deg to 90 deg over a 0.2s time period, the knee moves from 70 deg to 180 deg over 0.25s and the ankle moves from 110 deg to 80 deg over 0.1s. Which joint had the fastest angular velocity?

Knee

During the downphase of a squat, the knee starts at 175 deg and ends at 75 deg at the bottom of the squat. Which of the following muscles are responsible for this motion at the knee?

Rectus femoris

Which of the following is described as an object’s ability to resist angular motion?

Angular inertia

If the knee has coordinates of (1.2,2.7) and the ankle has coordinates of (1.5,2.1), with the shank weighing 3.2kg, what is the moment of inertia of the shank about the proximal end point? (%k = 0.528)

0.40 kg/m²

The radius of gyration for a body segment is smallest about which of the following reference points?

COM

The femur has a mass of 5.5 kg, a radius of gyration of 0.158m, and an angular velocity of 21 rad/s. How much torque was applied to the system to achieve the angular momentum if the torque applied was for 0.3s?

9.59Nm

The stick figure model reveal an athlete at the peak of a vertical jump. The athlete has an unconventional jumping style where they tick their legs while jumping. Use the (X,Y) data given to find the angle of the knee joint at the peak of the jump. What is the length of the shank segment?

48m

The stick figure model reveal an athlete at the peak of a vertical jump. The athlete has an unconventional jumping style where they tick their legs while jumping. Use the (X,Y) data given to find the angle of the knee joint at the peak of the jump. What is the length of the thigh segment?

49.81m

The stick figure model reveal an athlete at the peak of a vertical jump. The athlete has an unconventional jumping style where they tick their legs while jumping. Use the (X,Y) data given to find the angle of the knee joint at the peak of the jump. What is the angle of the knee joint at this point in time?

79.6 degrees

The throwing phase of a baseball pitching is 0.15s, shoulder flexion is 135 degree and elbow extension is 95 deg. If the arm length is 0.42m and the forearm length is 0.44m, what is the baseball’s linear velocity at the time of release?

11.46m

The hip is located at (20,68) and the knee (35,32) in a X-Y reference system (in meters), what is the angle of the thigh in relation to the right horizontal?

112.6 degrees

If I throw a baseball at 7500 deg/sec around my shoulder joint from a distance of 0.4, what is the radial acceleration of my arm?

6854.72 m/s²

The femur has a mass of 5.5 kg, a radius of gyration of 0.158m, and an angular velocity of 21 rad/s. What is the moment of inertia of the femur?

0.1373 kg x m²

The stick figure model reveal an athlete at the peak of a vertical jump. The athlete has an unconventional jumping style where they tick their legs while jumping. Use the (X,Y) data given to find the angle of the knee joint at the peak of the jump. If using the thigh and shank to make a triangle, what is the length of the third segment (“C”) in that triangle?

62.63m

The femur has a mass of 5.5kg, and a radius of 0.158m, and an angular velocity of 21 rad/s. What is the angular momentum of the femur?

2.877 kgm²/s

During an elbow curl, if the forearm has an angular acceleration of 10 rad/s², with the forearm length of being 0.2, and the angular velocity of 15 rad/s, what is the resultant acceleration?

45.04 m/s²

The hip is located at (20,68) and the knee (35,32) in a X-Y reference system (in meters). What is the thigh length?

39m